Case-hardening apparatus.



PATENTE-D APR. 7, 1908.

A. W. MACHLBT. CASE HARDENING APPARATUS.

APPLICATION FILED DEO.19, 1.905.

2 SHETS-SHEET 1.

"-III Witnesses PATENTED APR. 7, 1908.

A. W. MACHLET. v CASE HARDENING APPARATUS.

APPLICATION FILED DEC. 19. 1905.

z SHEETS-SHEET 2.

Witnesses Li.; Attorng iaiTEivr'i oEEioE.

AnoLrn w. MACHLET, or ELIZABETH, NEW JERSEY.

CASE-HBDENING APPARATUS.

specification of Lei-.segs resent.

ratentednprn?,

'pplcationled December 19,. 1905'. Serial No.- 292,515.

To all 'whom 'it may concern: A

Be it lknown that I, ADoLPH W. MACH- LET, acitizen of the United States, residing in Elizabeth, `in the county of Union and State of New Jersey, have invented certain new and useful Improvements in Case- Hardening Apparatus, of which the following is a speciiication.

This invention relates to the case-hardening of steel and iron articles', particularly small articles in bulk, by subjecting the articles when heated to a bath or current of carburizing gas.

The features-of the invention disclosed herein are in the nature of improvements upon the invention set forth in my pending application, No. 244,244 filed Feb. 4th, 1905, Patent No. 822,460.

When illuniinatin gas, which is rich in carbon, is employe as. a'case-hardening agent, a large part of the carbon in the gas'is de osited upon the articles and upon the- Wa of the retort'. This is not only a waste of material, but it is also apparent that the deposit of surplus carbon upon the surface 'of the articles prevents roper access of the gas to the articles, `thus elayino the completion of the process, and hence maIring it necessary to maintain theA heat for undue length of time, besides which the articles are not cemented evenly, there being a greater depth of cementation upon otherV portions of each.V

article than u ion the. portion Whichereceives: phe deposit o surplus carbon 'upon fthe suie'-vr ace.

O ne-of the-objects of my invention is to avoid this difficulty, and not only reduce the amount of carburizi'n gas vconsumed. and prevent'depositof surp us carbon, Vbut also to decrease the time required for'cementingthe articles to a given depth, and thereby reduce the-expense for maintaining`the heat of the retort. I also 'aim to render the case-hard'-V `ening even indepth and hardness all over thearticles,v articularly where an extremely thincaseis esired. u v f Another objectof the invention is*V to rolong the life of the retort and also to re iice the `expense of 'renewing the same when Worn out.4 In place of a cast-iron retort,

. 'having one or more 'partitions .cast therein and flanges cast thereon for various purposes, I form a retortwhich consists of a section of tuhingyyhich is made of soft steel and can readily bepurchased in this form,

although it may be made of Wrought iron. Upon this tubing I secure suitable collars, fianges and covers, and Within the tub' I insert partitionswhich are preferably y attached to the covers,-so as to be movable therewith; the space between the partitions in theretort being wholly Within the flame chamber in the furnace.

I aim to reduce materially the cost of casehardening articles, to insure that the case-v hardening operation shall produce a shell of uniform thickness all' over' the article, regardless of the shape, to regulate or gage eX,- actly the de th of cementation, andto make it practicab e to case-harden' small articles cheaply and rapidly in bulk and with uniformity. 'After cementation is completed, the articles may be tempered yin the manner described in my said application. I

- I heat the articles toa point above redness, but below the melting poi-ntin an atmosphere -of carburizing gas,preferabl above atmospheric. pressure. I referab y effect gentle agitation of the artic es diiring the cementation, so as to eX'pose all portions of the ,articles to the action of the gas. The heat may be-"froin about 150() to about 1800 degrees Fahrenheit. The progress of the. cementetion maybe known or predetermined and may be arrested at any point, the. thickness of theshell'being determinedinladvance even lt'oa thousandthparlt-off an inch.- y p The illuminating or carburizing gasfl cause topass through ammonia Water before entering the retort.v Bythis means, a ve lar e proportion of ammonia is taken u y t e carburizing gas. Preferablyinuch es's than half of the bulk of the gas entering the retort consistsof carbon. In this way, the deposit of surplus carbon upon the surface 'or exterior of the articles is avoided, or at leastreduced .to such an extent as toV benegligible, the process is much hastened, and a uni orm shell of higher quality than heretofore is produced.

In the-accompanying drawings, Figure l represents a sectional elevation taken from end to end of one forni of an ap aratus con.- structed for Vcase-hardening an Vtempering ,an elevation of the left-hand end and Y g. 3 'an elevation of the right-hand end' of the c arburizing apparatus seen at Fig. 1. Fig. a is a vertical cross-section taken near the leftarticles according to my invention. Y F1 .2 is j hand end of the furnace at Fig. 1. Fig. 5 is a sectional plan illustrating the means of attaching the flange to'the end of the tubing which forms the retort. Fig. 6 is a diagram illustrating the connections to the retort.

The steel or iron articles to be case-hardened,rrepresented by a dotted line 1, are de-v posited in bulk within a retort 2, preferably.,

at 10.` The. space inclosed by said refractory lining, forms said flame chamber. Any suitable fuel may be consumed in the furnace; and it may be otherwise constructed. Preferably a mixture of liydroc'arbon fuel With air is used, the airlieing admitted through apipe 11, and the fuel, such as ordinary illuminating or heating gas, being admitted'through a pipe 1 2 g the supply ofair and fuel being re ulated by 'valves`13, 14. ,The airandffuel ecome mixed within the pipes 15, 16., and the mixture is admitted to burners 17, 18,`in serted in horizontal openings 19, 20,'formed in the op osite walls of the furnace near the top of tie flame chamber.. The burners polnt alternately in opposite directions, as seen at Fig.4,` so as to direct the flames across the top and down around both sides of the retort, and form two sets, ex-tending along the top of the flame chamber above said retort. Two feed pipes 21, 22, extending along the furnace connect the burners in the sets g said pipes being supplied by the pipe 16, which extends across the top of the urnace. The gas flames are directed upon and over the retort and play down around the same and escape through an outlet'23 formed in the bottom of the furnace at the end of the. retort, whereby even heating of the latter is assured. The supports of'said retort are mounted upon the exterior of the furnace heads, and consist of a pair of rolls 24 carried upon brackets 25, fixed upon the lefthand head 7, and a pair of rolls 26 mounted upon brackets 27 fixed upon the right-hand head 6. The retort consists of a section of wrought iron or soft steel tubing, which is readily purchasable in thisI form, and coniprises the main chamber, in which the articles 1 are placed, and extensions 28 and 29 projecting from the ends of the furnace, the

extension 28 revolubly mounted upon the rolls 24, and the extension 29 upon the rolls 26. Said extensions project through openings 30 formed in the refractory lining 9 and through similar openings in the heads of the furnace.

Inserted in the retort are two partitionsv The cover 34, .which is-provided Withan-i asbestos orother packing 37, is securedvby bolts 38 to a flange or Wheel 39, Wh-ich isidetachably secured'by set screws 40, Fig. 5, and is provided with an annular recess 41', which forms a tread to run upon the rolls 24; the flanged walls of -said recess serving to prevent endwise displacement of the retort.

The cover 36, which is provided With an asbestos packing 42, is secured by bolts 43 and Wing nuts 44 to a collar 45, which is detachably secured upon the retort by bolts 40 in the same manner as seen at Fig. 5. The space between the partitions 31, 32 is wholly within the flame chamber of the furnace, and

separated from its flanges, covers and par-l titions, and a new one inserted upon Which the same attachments may be employed.

' The carburizing as may be a pure hydrocarbon, although have found in practice that good results are obtained by the use of ordinary cit gas.

The gas W ichis used for cementation may be su plied undery ressure in anyfsuitable Way, lint for the sa e of illustration, I have shown a gas receiver or tank 46, which contains gas preferably under pressure. In some cases the pressure may be just a little higher than atmos heric pressure; or it may vary from just su cient to Charce the retort, to the highest that may be found practicable. This receiver is connected to the retort by means of apipe 47, provided with a valve 48, and a pipe or elbow 49, the latter being in line With the` axis of retort 2. A gland is shown at 50 to accommodate the rotation of the retort, since the pipe 49 remains stationary. A yoke or bracket 51 is fixed ulpon the head 7 of the furnace to support the and 50, into which pipe 49 is threaded. T e' latter is provided w1th a cap 53, which may be removed to giveaccess to the interior of the pipe and gland for cleaning. Threaded into the end o the retort, is a spray pipe 54, having numerous apertures 55 for directing the gas in small jets into the retort; said sprayer 54 being connected by the pipe 33 to the gland 50. nearly the entire length of the retort, so as to insure that articles throughout the retort shall be acted upon by gas of uniform quality.

In operation, the retort is charged with articles and the gas in the furnace is ignited `and the .retort heated thereby, until the The sprayer'54 may extend for ing therefrom igniting and constantly burning. By means of the valve 58, the duration of the stay of the gas in the retort may be r ulated.

he furnace 'maybe provided with a sight hole 59 and a pyrometer 60, whereby the I operator may determine precisely when the articles have retained the required heat for cementation.

In a rece tacle 61, Fig. 6, I` place water 62 which is c arged -with ammonia; and lby means of a pipe 63 I lead the gas from the holder 46 through the ammonia water, whereby the gas becomes charged with ammonia and passes from the receptacle 61 through a pipe 64 and the gland 50 and inlet 33 tothe retort 2. The i e 63 terminates in a spray 65 below the su ace of the ammonia water, so as to insure a thorou h charging of the gas with the ammonia. T e, receptacle 61 may be heated by placing the same in al vessel of hot water or by surrounding the same with a heating coil 66 or otherwise, in order to keep the temperature of the ammonia sufficiently high for mixing well with the gas; ora temrature of about 190 vdegrees Fahrenheit eing preferable. The spent ammonia water may be drawn off through an outlet 67, and the receptacle refilled from a tank 68# The valve 48 may be kept closed, so that the gas from the gas-holder 46 may be passed through the ammonia water, whereby the l the carburizin 48 may be openeda little, so as to `Vthro Valves 69, 70. may be carburizing as is thinned to an extreme degree, the bl k of the ammonia enterin the retortbein much greater than the bu k of p gas. If'however, a lar er proportion of t e latter is desired, the va ve ermit some gas to pass from the holder 46-d1rectly to the --retort 2, while other. gas passes ugh' the ammonia water into the retort. rovided upon the pipes 63 and 64 to facilitate the control of the gas and ammonia. By this means, but little, if any more carburizing gas is admitted to the retort than is taken up. by the iron or steel articles therein, sothat deposit of excess carbon upon said articles or upon the Walls of the retort is avoided.

l Rotation of the retort during. the carburizing operation is effected by means of a worm tort.

71 operated b a pulley 72, and meshing with a Worm Whee 73 formed upon the cover 34; whereby the articles are gently agitated, and all rtlons thereof exposed with substantial ormity to the action` of the gasin the re- Variations may be resorted to within the said retort closed at one end .and provided at,

the other end with a movable cover, a partii tion within said retort and rigidly attached to said cover, and means for passing iron-carburizing gas through said retort during its rotation. v

3. A furnace containing a revoluble retort, said retort closed at one end and provided at the other end with a movable cover, a partition within said retort and attached to said cover, and means for passing iron-carburizing gas throu h said retort during its rotation; means eing rovided for clam ing said cover, and a pac ng bein@ provide between said cover and the end of said retort.

4. A furnace containing a revoluble retort, said retort provided| at its endswith covers, and partitions within said retort, one partition attached to each cover so as to be movable therewith, and means for passing ironcarburizing as through said retort; means being provi ed for clamping each of said covers, and packings lbeing provided between said covers an the ends of said retort.

5. A furnace containing a revoluble retort, the ends of'said retort projecting from the furnace' and being supported upon rolls, one end of said retort being closed, the other end having a movable 'cover packing; and partitions wit n said retort at such points that the space between the artitions is wholly within the flame cham er of the furnace ;'one of saidpartitions being connected to said cover so as to be movablev furnace and being supported upon rolls, each end of said retort provided with a movable cover and apacking, partitions within said retort at such voints that-the space between them is whollg)T rovided with a within the flame chamber of the furnace; said partitions being connected one to each of said covers so as to be movable therewith; and means for passing ironcarburizing gas through said retort during the rotation thereof.

7. A'case-hardening lapparatus comprising a furnace containing a retort closed at one end, a movable cover-for the other end of said retort, a removable partition within said retort, and an open pipe securing said partition to said cover, and means for passing a current of iron-carburizing gas through said retort.

8. A case-hardening apparatus comprising a furnace containing aretort having a movable cover at each end, removable partitions witl'iin said retort, open pipes securing said partitions to said covers, and means for causmg a current of iron-carburizing gas to floW through' said pipes.

E). A mise-hardening apparatus comprising a furnace containing a retort closed at one end, and provided with an inlet, a movable cover secured to the other end of the furnace and provided with a packing, a partition within th(` retort, and a vent pipe connecting said partition to said cover.

10. A case-hardening apparatus comprising a furnace containing a retort having covers at. its ends and partitions between its cnds,.and inlet and outlet pipes connecting said partitions to said covers.

l1. A case-hardening apparatus comprising a furnace containing a retort having covers at its ends, partitions between its ends, an inlet. pipe connecting one of said covers to one of said partitions, and a vent pipe connecting the other of said covers to the other of said partitions.

12. .A furnace containing a retort and pro.- vided ith rolls upon which the retort re. volves, said retort having covers, partitions at such points within the retort that the space u ithin them is entirely ithin the `flame-chamber of the furnace, an inlet pipe securing one of said partitions to one of sald covers, a gland for said inlet pi e, and avent pipe securing the other of sai( partitions to the other of said Covers.

13. A furnace containing a retort, said retort provided at its ends with movable cov- `ers, and partitions uithin said retort, said partitions attached to said covers, and a space between said partitions lying wholly within the flame chamber of the furnace, and the ends of said retort rojectingfrom the furnace and being revolu ilyl supported upon the exterior of the furnace. p

14. A furnace containing a retort, the lat,- ter having movable covers at its ends, said ends projecting from the furnace, and partitions vi ithin the retort and connected to said covers to be removable therevith, the space between said partitions being wholly within the flame chamber of the furnace, and means for supplying carburizing gas to -and\ venting it from said retort.

15. A furnace containing a retort, means being provided upon the exterior of the furnace for revolubly supporting the retort., partitions within the retort at such points that the space bet een the partitions is Wholly ithin the fiame chamber of the furnace, a

cover atone end of the retort and rigidly connected to one of said. partitions, a packing forsaid cover, and means for passing a cur rentv of iron-carburizing gas through said retort during the revolution thereof.

16. In a case-hardening ap aratus, the combination with a furnace, o a retort extending through the furnace, and consisting of Aa section of tubing of soft steel or wrought iron, rolls supporting said retort for revolution, covers detachably connected to thc ends of said retort, partitions applied to the A interior of said retort, and means for passing a current of iron-carburizing gas through said retort. l

17. In a case-hardening apparatus, the combination with a furnace, of a retort extending through the furnace, and consisting ofa section of tubing of soft steel or Wrought iron, rolls upon which one end of the retort is supported, a tire detachably secured upon the other end of said retort, rolls upon which said tire runs, said tire having a flange to prevent endwise displacement of the retort, a

cover detachably connectedto said flange, gearing connected to said cover, a collar detachably secured upon the other end of said retort, a removable cover connected to said collar, and partitions within said retort and connected to said covers.

18. In a case-hardening apparatus, the combination' with a.fur'nace, of a retort extending through the furnace and consisting of a section of tubing, covers detachably connected to the ends of said retort,l detachable partitions within said retort, and means for'l passing a current of iron-carburizing gas through said retort.

19. In a case-hardening apparatus, the

combination With a furnace, of a retort extending through the furnace and consisting of a section of tubing, covers detachably connected tothe ends of said retort, detachable partitions Within said retort., and means. for passing a current of iron-c'arburizing gas through said retort; and means exterior to said furnace for revolubly supporting saidl combination with a furnace, o a retort extending through the furnace and consisting of a section of tubing, covers detachably connected to the ends of said retort, rolls upon which the retort is revolubly mounted, parti.- tions within the retort, one of said partitions rigidl connected to one of the covers, means detac lably connected to the 'retort for effectfrom the retort.

l 22. In a case-hardening apparatus, the combination with a furnace, of aretort extending through the furnace and consisting Y of a section of tubing, covers detachably consaid gear, a

nected to the ends of said retort, rolls upon which the retort is revolubly niounted, partitions within the retort, one of said partitions rigidl connected to one of the covers, means detac ably connected to the retort for effecting revolution thereof, and means for admitting iron-carburizing gas to rand venting it from the retort; one of said covers having a gear provided thereon, and means for driving said gear.

23. In a case-hardening apparatus, the combination With a furnace, of a retort extending through the furnace and consisting of a section oftubing, a cover detachably connected to one end of said retort, a gear provided upon said cover, means for driving partition within said retort, an inletpipe rigidly connecting said partition to said cover, a gland connected to said inlet pipe, means revolubly supporting said retort,

a cover for the other endvof said retort, and a partition connected to the last-mentioned coverby means of an outlet pipe.

24. In a case-hardening apparatus, the combination with a furnace, of a retort extending through the furnace and consisting of a section of tubing, a flange detachably secured upon said section, a cover detachably' connected to said flange and'having a gear,

means for driving said gear, rolls upon which said retort is revolubly mounted, said flange being constructed to coperate with some of said rolls to prevent endwise displacement of the retort, a partition within said retort and rigidly connected to said cover, a detachable collar upon the othery end of said retort, a cover connected to said collar, a partition Within said retort and connected to the lastmentioned cover, and -regulatable means for passing a current of iron-carburizing gas Ithrough said retort during the revolution thereof. p i 1 25. In a case-hardening apparatus comprisin a closed retort formed of metal and provied With means to permitfrestricted venting of vitiated gas during the c'arburizing operation, and also having means for causing the retort to heat quickly and uniformly throughout to a degree suitable for carburizing steel articles therein, and for maintaining a substantially .even temperature of the retort throughout the carburizing operation, the combination with means connected to the retort lfor furnishing thereto a supply of fresh carburizing-gas during the carburizing operation, of means also connected to the retort for su plying thereto simultaneously with the car urizmg-gas a plenum fore it enters the retort, with a .ing operation, and also Ahavln causing the retort to heat quic y and unisupply of fresh carburizing-gas during the'. carburizing o eration, of means connected to 4of suitable gas for diluting the carburizing said gas-supp ying means for mixing the cal-, l

burizing-gas, before it enters the retort, with a plenum of suitable gas for diluting the carburizing-gas, and means to agitate the articles during the carburizing operation.

27. In a case-hardening apparatus comprising a closed retort formed of metal and provided with means to permit restricted venting of vitiatedA gas during the carburizing o eration, and also having means for causing t e retort to heat` quickly and uniformly throughoutto a degree suitable for carburzing steel articles therein, and for maintaining a substantially even temperature of the retort throughout the carburizing operation, the

combination With means connected to the retort for furnishing thereto a supply of fresh carburizing-gas during the carburizing operation, of means connected tosaid gas-supplying means for mixing the carburizing gas, be-

lenum of ammonia and means tov agitate t e articles during the carburizi'ngjoperation.

28. In a case-hardemng a parats comprising a closed retort forme of metal and provided With' means to permit restricted venting of vitiated gas during the carburiz-` j ing operation, and also having means for caus-v ing the retort to heat quickly and uniformly throughout toa degree suitable for carburizing steel articles therein, and for maintaining a substantially even temperature of the retort throughout the carburizing operation, thecombination With means connected to the retort for furnishing thereto a supply of fresh carburizing-gas during the carburizing operation, of means connected to said gassupplying means for mixing the gas before it enters the retort, with a'plenum of ammonia, and means for heatin the ammonia to a sufficient de ree to ena le it to mix properly with the car urizing gas.

29. In a case-hardening a paratus comprising a closed retort forme of metal and provided With means to permit restricted venting of vitiated gas during the oarburizmeans for formly throughout to a degree suitable for carburizing steel articles therein, and for maintaining a substantially even temperature of the retort throughout the carburizing operation, the combination With means connected to the retort for furnishing thereto a supply yof fresh carburizing gas during the carburizing operation, of a receptacle for ammonia Water connected to said gas supply; means being prov'ded to cause the gas to pass through the water before entering the retort; and means to agitate the articles during the carburizing operation. Y

30. In a case-hardening apparatus comprising a closed retort formed of metal and provided With means to permit restricted venting of vitiated gas during the carburizing operation, and also having means for causing the retort to heat quickly and uniformly throughout to a degree suitable for carburizing steel articles therein, and for maintaining a substantially even temperature. of the retort throughout the carburizing operation, the combination with means connected to the retort for furnishing thereto a supply of fresh carburizing gas during the carburizing operation, of a receptacle for ammonia Water connected to said 'gas supply; means being provided to cause the gas to pass through the Water before entering the retort; and means for heating said receptacle; and means to agitate the articles during the carburizing operation.

31. In a case-hardening apparatus comprising a closed retort formed of metal and provided With meansvto permit restricted venting of vitiated gas during the carburizing operation, and also provided with means for maintaining the retort throughout the carburizing operation at a substantially even temperature suitable for carburizing, the

combination With means for effecting slow rotation of the retort during the carburizing operation, of means connected with the retort for supplying thereto carbuiizing gas during the rotation of the retort, and ymeans also connected with the retort for supplying thereto simultaneously With the carburizing gas a plenum of suitable diluting gas.

32. In a case-hardening apparatus comprisinga closed retort formed of metal and provided with means to permit restricted venting of vitiated gas during the carburizing operation, and also having means for causingy the retort to heat quickly and uniformly throughout to a degree suitable for carburizing steel articles therein, and for maintaining a substantially even temperature of the retort throughout the carburizing operation, the combination with means connected to the retort for furnishing thereto a supply of fresh carburiZing-gas during the carburizing operation, of a spray pipe Within the retort to receive the fresh carburizing gas and extending throughout the retort to distribute the gas with substantial evenness to the articles filling the retort, and means for rotating the retort during the carburizing operation.

33. In combination, a furnace having a flame chamber, a retort in the form of a barrel having ends, hollow supports extending from said ends and projecting from the furnace, and revolubly mounted exteriorly of the furnace, one of said ends` being in the form of a removable cover, a pipe extending through the other of said ends and terminating outside of the barrel in a gland, by which carburizing gas is supplied to the barrel during its rotation, and a spray pipe forming a continuation of said pipe and extending therefrom Within the barrel substantially the v entire length of the barrel.

ADoLPH W. MAci-ILET.

Witnesses:

SAMUEL R. OGDEN, PHILIP C. OSTERMAN. 

